•Hydrolysable tannins are the main phenolic compounds identified in walnut kernels.•Glansreginin A is the most abundant compound in peeled walnut kernel.•Castalagin and casuarin isomers are the most ...abundant compounds in walnut kernel.•13 new compounds are identified in peeled walnut kernel, and 14 in walnut pellicle.
This study was designed to identify and quantify the major phenolic constituents in peeled kernel and pellicle of the walnut Juglans regia L. Data were compared across six different cultivars: 'Fernor', 'Fernette', 'Franquette', 'Sava', 'Krka' and 'Rubina'. High-performance liquid chromatography coupled with mass spectrometry was used to identify and quantify these compounds. Nineteen ellagitanins, 12 ellagic acid derivatives, 4 anthocyanins and 5 other phenols were identified in the pellicle of these walnuts, and 15 dicarboxylic acid derivatives and 1 phenol in the peeled walnut kernels. Thirteen previously unreported compounds were identified in the peeled walnut kernels, and 14 in the walnut pellicle. Hydrolysable tannins were the main phenolic compounds identified in the walnut kernels, and accounted for 31.0% to 35.1% of the total phenolics analysed. The highest intake of total phenolics content per walnut kernel can be obtained by consumption of 'Franquette' and 'Rubina', with the lowest for 'Krka'.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The distribution of betalains in peel, flesh, and petioles of yellow and red beetroot cultivars has been investigated using an High‐performance liquid chromatography (HPLC) system with electrospray ...mass spectrometry. Differences in the levels of betacyanins and betaxanthins between different colored cultivars were individually determined for 3 plant parts. The content of almost all analyzed compounds decreased in the following order: peel > flesh > petiole. Betanin/isobetanin pigments comprised a major portion of the relative peak area measured in red beetroot peel. Isobetanin relative peak areas were also high in leaf petioles (68.94% to 74.16%) of red colored cultivars. However, betacyanins were completely absent from the extracts of all analyzed parts of yellow beet. Glutamine‐bx represented a very high relative peak area (59.54% to 64.18%) in flesh of red‐colored cultivars analyzed in the study. Our results indicate that red beet cultivars can be utilized as a potential source of red and yellow natural colorants. However, differences in pigment composition among different beetroot parts must be considered and in order to maximize the pigment yields petioles can also be used as a source rich in specific betalain compounds.
Practical Application
The studies on plant material with high betalain levels can provide new opportunities for the use of these healthy pigments in the food and pharmaceutical industries. Further investigations on highly concentrated betalains in various cultivars/plants parts can help elucidate their biological activity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Berry fruit is known for its high contents of various bioactive compounds. The latter constitute of anthocyanins, flavonols and flavanols and posses high antioxidative activity. The highly dynamic ...antioxidant system can be evaluated in vitro and in vivo in several model organisms. These measurements represent a good approximation of the real potential of bioactive compounds in the cells of higher eucarions. The aim of the study was thus to determine in vitro and in vivo antioxidant activity of different berry juices, which reportedly contain high amounts of phenolics.
Five different berry species were collected from several locations in central Slovenia and juice was extracted from each species separately. Juice was assessed for their in vitro and in vivo antioxidant activity. Phenolic profiles of berries were determined with the use of a HPLC/MS system, in vitro antioxidant activity with the DPPH radical scavenging method and in vivo antioxidative activity using Saccharomyces cerevisiae. The highest diversity of individual phenols was detected for bilberry juice. The highest in vitro antioxidant capacity was determined for blackcurrant juice. A decrease in intracellular oxidation compared to control was observed in the following order: blackcurrant < chokeberry = blueberry < bilberry. The results indicate important differences in antioxidant activity of berry juices between in vitro and in vivo studies.
In addition to the total content of phenolic compounds entering the cells, a key factor determining antioxidative activity of berry juices is also the ratio between the compounds. Where high content levels of anthocyanins and very low content levels of flavonols and hydroxycinnamic acids were measured a lower intracellular oxidation has been detected. Specifically, intracellular oxidation increased with higher consumption of hydroxycinnamic acids and lower consumption of anthocyanins in the cells. Antioxidative activity also increased when the consumption of analyzed phenols was rather low.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present study was designed to identify and quantify the major phenolic compounds (phenolics) in the inner and outer husks, buds and bark of the Persian walnut,
L. A comparison across six ...different cultivars grown in Slovenia was also carried out: 'Fernor', 'Fernette', 'Franquette', 'Sava', 'Krka' and 'Rubina'. A total of 83 compounds were identified, which included 25 naphthoquinones, 15 hydroxycinnamic acids, 8 hydroxybenzoic acids, 13 flavanols, 2 flavones, 1 flavanone and 19 flavonols. For the first time, 38 phenolics in the husks, 57 phenolics in the buds and 29 phenolics in the bark were presented in
within this study. Naphthoquinones were the major phenolics determined, approximately 75% of all analysed phenolics in the inner husk, 85% in the outer husk, 50% in buds and 80% in bark. The highest content of phenolics was found in the walnut buds, followed by the bark, the inner husk and the outer husk. On the basis of these high phenolic contents, walnut husks, buds and bark represented valuable by-products of the walnut tree. These data also show origin-related phenolic contents across the cultivars, and thus these phenolic profiles might serve to define the origins of different walnut cultivars.
The present study was designed to characterise and quantify the major phenolic constituents in healthy leaves and leaves infected with Xanthomonas campestris pv. juglandis. A comparison among six ...different cultivars: 'Fernor', 'Fernette', 'Franquette', 'Rubina', 'Sava' and 'Krka', with the same agricultural, geographical and climatic conditions, was made. Liquid chromatography coupled with a mass spectrometer (HPLC-MS/MS) was used to identify and quantify the compounds. A total of 52 compounds were identified based on mass spectra and literature. Among them, 15 hydroxycinnamic acids, 6 flavanols, 2 flavones, 22 flavonols and 7 naphthoquinones were identified. Two flavones and three naphthoquinones were reported for the first time in J. regia leaves. In addition, two naphthoquinones, which are reported to play an active role in the process of juglone formation, were confirmed in all six cultivars. In the process of MS fragmentation, compounds were fragmented up to MS6 fragments and in some cases both MS2 fragments were further fragmented, providing comprehensive data. Total analysed phenolic content (TAPC) and total phenolic content (TPC) concentrations were higher in infected leaves, suggesting that phenols play a major role in plant defence. In the case of walnut bacterial blight, the contents of flavanols and total hydroxycinnamic acids were higher in infected leaves in all cultivars, suggesting that they could play a key role in a plant’s response to this economically important disease.
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GEOZS, IJS, NUK, OILJ, SBJE, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
ABSTRACTStrawberries intended for processing are usually frozen to withstand storage and distribution. However, freezing and thawing can cause the degradation of bioactive compounds. The aim of this ...study was to determine the optimal conditions for frozen storage and thawing to minimize any loss of nutrients prior processing. Different freezing treatments (−20°C, shock-freezing with liquid nitrogen, −80 °C) up to 6 months of storage and thawing treatments (4°C, room temperature, 37°C, microwave) were compared based on the content of organic acids, sugars, and phenolic compounds as well as the activity of peroxidase and polyphenol oxidase. During frozen storage at −20°C over 6 months, the sucrose content decreased by 59%, but only a 17% loss of ascorbic acid was observed, and no significant loss of anthocyanins was detected. However, more significant changes in composition were detected after thawing. When thawed at 4°C for 24 h, ascorbic acid content decreased by 32%, anthocyanin content by 30%, and sucrose content by 66%. Based on our study, the frozen storage caused smaller changes in the fruit’s composition than thawing. From the thawing procedures, the microwave thawing showed minimal changes in the composition of strawberries.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Knowledge of the physiology of natural fruitlet shedding is especially important to insure thinning efficiency in apple production. The effect of partial spur leaf removal on shedding, as well as on ...fruit quality and bourse shoot growth, was investigated. Removing spur leaves increased shedding, while there was no effect of partial leaf removal on mature fruit quality in terms of weight, firmness and sum of sugars, detected by HPLC-RI and resulted in lower contents of citric, fumaric and shikimic acids, detected by HPLC-UV. Growth of bourse shoots was poorer in treatments with leaf removal. To summarize, a decreased number of spur leaves caused more intensive fruitlet abscission and poorer bourse shoot growth but had no negative influence on fruit size. These results show the potential use of decreasing spur leaf area to stimulate more intensive natural shedding to support fruitlet thinning, which could be used in combination with prospective mechanical thinning.
In whole hazelnut kernels, as the main product of hazelnut (
Corylus avellana L.), phenols were analysed in 20 hazelnut cultivars by high-performance liquid chromatography–tandem mass spectrometry ...(HPLC–MS). Twenty-three compounds from different phenolic groups were detected, and 15 of them were identified. In hazelnut kernels, these substances were detected: nine flavan-3-ols, two benzoic acids (gallic and protocatechuic acid), three flavonols and phloretin glycoside. Total phenol concentrations ranged from 70 to 478
mg gallic acid equivalents per kg hazelnut kernels. A high content level of total phenols was observed in the ‘Tonda Gentile delle Langhe’ and ‘Lewis’ cultivars, which was followed by the ‘Corabel’, ‘Fertile de Coutard’, ‘Daria’ and ‘Tonda Gentile Romana’ cultivars. Similarly, the highest antioxidative activity, measured by employing DPPH-antiradical assay, was also found in the ‘Tonda Gentile delle Langhe’ cultivar, followed by the ‘Fertile de Coutard’.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In recent years, new approaches to intensive blueberry (Vaccinium corymbosum L.) production have become necessary, in terms of protected environments and planting systems. These are designed to avoid ...numerous production difficulties, such as market saturation, damage from hailstorms, bird attacks, and spring frosts, and specific soil property requirements. Use of high tunnels and planting in a custom substrate (e.g., pots, along ridges) have gained interest among growers in recent years. As in our previous study, we determined the performance of three blueberry cultivars, ‘Duke’, ‘Aurora’, and ‘Brigitta’, when planted in pots and along a ridge under a high tunnel. Substrate water content was maintained at the same level for the pots and the ridge, although the substrate temperature fluctuations were greater for pots. Plant growth in pots was significantly lower for ‘Duke’ and ‘Aurora’ compared to the ridge. Additionally, for ‘Aurora’, the fruit yield was significantly lower for pots (103.4 g/plant), compared to the ridge (315.2 g/plant), although the opposite was seen for ‘Brigitta’ (122.4 vs. 93.5 g/plant, respectively). Individual sugar and organic acid contents mostly coincided with total contents, with lower total sugars for ‘Duke’ and higher total organic acids for ‘Aurora’ and ‘Brigitta’ for pots. For ‘Duke’ and ‘Brigitta’ fruit, the contents of some individual phenolics showed significant differences between treatments for phenolic acids and flavonols. These data show that growth in pots can be a useful planting method for the blueberry cultivars ‘Duke’ and ‘Brigitta’, and high yields and good fruit quality can be attained by following correct technological measures.
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